1. Field of the Invention
This invention relates to a core/sheath type temperature-sensitive shape-transformable composite filament. More particularly, it relates to a core/sheath type temperature-sensitive shape-transformable composite filament useful as an artificial hair for doll hair (the hair of the head of a doll) and wigs or as a thermally shape-transformable fiber material, that is transformable to any desired shapes upon application of an external stress in a temperature region not lower than a temperature about the glass transition temperature of a specific thermoplastic polymer and lower than its melting point, and has the function to become fixed to the transformed shape in a temperature region lower than the glass transition temperature.
2. Related Background Art
Fibers of a vinylidene chloride type, vinyl chloride type, polyamide type or polyolefin type or fibers comprised of an acrylic polymer containing vinyl chloride and vinylidene chloride in a prescribed proportion are conventionally known as fibers for doll hair.
In the case of the doll hair making use of the above fibers, the hair style can not be transformed unless it is done at a high temperature not lower than the melting point of the fibers and also using a special tool. Thus, e.g., infants can not curl the hair to play with at will.
Under such circumstances, it is proposed in Japanese Patent Application Laid-open No. 10-1545 (U.S. Pat. No. 5,895,718) that a specific thermoplastic resin and a thermoplastic polymer having a glass transition temperature within the range of from -20.degree. C. to 70.degree. C. are blended in a specific proportion to obtain various molded products that function to be transformed upon application of an external force under low-temperature and fixed to the transformed shape by cooling.
The molded products proposed therein are applicable as shape-transformable toy shapes of various types and shape-transformable filaments.